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Rear Damper Data Point

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wyshyvanuk
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Rear Damper Data Point

Post by wyshyvanuk » Sun Sep 23, 2018 12:49 am

Just pulled one of the original rear dampers on my 2008 Z4M Roadster with 46K miles. Completely shot. It collapses with relative ease, and, once collapsed, stays there without a hint of any effort to expand again.

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Rear Damper Data Point

Post by mmm-five » Sun Sep 23, 2018 9:11 am

Data point 2:

Mine was on the originals all the way to about 120,000 miles (obviously past their best, but not 'broken' per se). Then I replaced the lot with Bilstein PSS10.
Trigger’s Z4MC
Some bits now over 163,000 miles, some less than 1,000 miles.
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MrPT
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Rear Damper Data Point

Post by MrPT » Sun Sep 23, 2018 9:41 am

wyshyvanuk wrote: Sun Sep 23, 2018 12:49 am Just pulled one of the original rear dampers on my 2008 Z4M Roadster with 46K miles. Completely shot. It collapses with relative ease, and, once collapsed, stays there without a hint of any effort to expand again.
Thanks for posting this, but what do you mean “expand again”? It’s a damper so should resist force in both directions when unsprung.
2008 Z4MC: heavy wheels | crap suspension | skittish rear end | wobbly engine | not enough induction noise | underwhelming turn in | inconsistent braking | lardy battery | chubby steering wheel
2006 Z4 2.5si: gone

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wyshyvanuk
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Rear Damper Data Point

Post by wyshyvanuk » Sun Sep 23, 2018 1:58 pm

Quite true, but they are also gas pressurized. When mounted, the barrel spring supporting the weight of the car will partially collapse the damper against that gas pressure. When a dip or pothole is encountered, that gas pressure will assist the spring in pushing the wheel down to maintain contact with the road surface.

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wyshyvanuk
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Rear Damper Data Point

Post by wyshyvanuk » Sun Sep 23, 2018 2:16 pm

mmm-5, I now have a serious case of suspension envy.

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